A new study appearing in BMJ Open compared rates of prostate cancer in dozens of countries worldwide with oral contraceptive use and finds countries with more use of oral contraceptives have higher rates of prostate cancer incidence and mortality. The authors, two researchers at Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada, speculate that by-products of oral contraceptive use could be passed via urine into the environment in general or drinking water, thus exposing the population at large. Below are comments from Eric Jacobs, PhD, strategic director of pharmacoepidemiology in response to the report.

“This ecological analysis reports that countries with higher rates of oral contraceptive use tended to have higher rates of prostate cancer. The authors speculate this association could be due to estrogens from oral contraceptives reaching drinking water, although levels of estrogens in drinking water were not measured in this study.”

“Concerns have previously been raised about the environmental and health effects of endocrine disruptive compounds, including estrogens from oral contraceptives. However, results of ‘ecological’ analyses like this one, that compare countries, rather than individual people, must be interpreted cautiously. Many lifestyle and medical care factors vary between countries, therefore differences in cancer rates between countries can be difficult to ascribe to particular factors.”